After posting this, I went on to work on another area of the site, which I completed, and today went back to look at this and miraculously the translations started appearing. not sure what I did but make sure all site translations are in the folder /application/languages/site/<locale>.mo. So I.e. for German it would be /application/languages/site/de_DE.mo and make sure you clear your cache if it's enabled. Hope that helps.